Psychopaths are irresponsible and unreliable. They do not honor contracts, undertakings, and obligations. They are unstable and unpredictable and rarely hold a job for long, repay their debts, or maintain long-term intimate relationships. Psychopaths are vindictive and hold grudges. They never regret or forget a thing. They are driven, and dangerous. Always in conflict with authority and frequently on the run, psychopaths possess a limited time horizon and seldom make medium or long term plans. They are impulsive and reckless, aggressive, violent, irritable, and, sometimes, the captives of magical thinking, believing themselves to be immune to the consequences of their own actions.
Thus, psychopaths often end up in jail, having repeatedly flouted social norms and codified laws. Partly to avoid this fate and evade the law and partly to extract material benefits from unsuspecting victims, psychopaths habitually lie, steal others' identities, deceive, use aliases, and con for "personal profit or pleasure" as the Diagnostic and Statistical Manual puts it. (From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase: http://www.narcissistic-abuse.com/thebook.html)